The relationship between formal education and health is strong, broad, and persistent. When presented with such a robust association, it is natural to make the leap, implicitly if not explicitly, to a presumption of causality. A causal connection has a certain intuitive appeal, and economists and sociologists have developed conceptual models of health that incorporate and elaborate on how such a causal relationship might operate. However, some have questioned the causal link on both conceptual and empirical grounds, arguing that the apparent relationship between education and health might in fact be due in some part to third factors, such as time preferences or self-efficacy, common to both educational attainment and health, but generally omitted from empirical models. The proposed study will employ a relatively data-rich longitudinal dataset and instrumental variables methods to investigate the nature of the observed relationship between education and health. Specifically, the study has the following aims: Aim 1: To explore the determinants of educational attainment in youth, and specifically to evaluate the effect of youth health on educational attainment; Aim 2: To examine the extent to which estimates of education's effect on health behaviors and health status are robust to the exclusion of frequently omitted variables; Aim 3: To estimate the causal effect of education using instrumental variables methods. Relevance The four behaviors to be studied are among the ten Leading Health Indicators for Healthy People 2010, reflecting their importance in shaping our Nation's health. Education is both an important element of socioeconomic status and one sensitive to policy intervention. Improving our understanding of how education influences health behavior will further the goals of Healthy People 2010.